In Theory
by Rylitah
Summary: Kaito's got a whole list of cheesy and awful pickup lines to use on Shinichi. (Un)fortunately for him, Shinichi's got just as many to throw back. / Kaishin, silly little oneshot.


"What's that?"

Shinichi raised an eyebrow at the rather thick stack of paper Kaito was holding. The first thing that came to mind was that the magician was trying to memorize something big for his upcoming magic show – but that was impossible, because he was always under the impression that Kaito could just _will_ anything into his memory and it would remain there for the rest of time.

It was almost scary, how good his memory was.

"Did it hurt?" Was Kaito's sole response, and Shinichi's first thought was _that was not an answer to my question_. But he'd play along.

"Did… what hurt?"

He hadn't been on any cases recently – wait, no, scratch that, he hadn't been on any _dangerous_ cases recently. The cases he's had to solve in the past few months have just been the same old routine: victim is murdered, gather the evidence, corner the criminal, cue emotional breakdown. Not that he was complaining – Kaito tended to get overly _clingy_ whenever he was faced with a retaliating foe. And while that was nice in itself, it had the potential to get annoying very quickly, as Kaito would not let _go._

So he didn't really know what he was going on about.

"When you fell from heaven," Kaito allowed himself a sly grin and leaned closer to Shinichi with half-lidded eyes.

Shinichi twitched. Oh. Now he understood.

"I'm not dead."

He would have snorted at the confused look that crossed Kaito's face at his response, but before he could open his mouth to say another word, the magician was already furiously reading back through his stack of pages. "Forget it, then," he said. "Try this one: Do you have a map?"

"Well," Shinichi looked around and spread his arms. They were in a library – _his _library, to be exact – he was pretty sure they'd have plenty of maps around for whatever Kaito wanted to know his way around. But he could already see where this was going. "Take a look around you."

"Shinichi, just go along with it," Kaito sighed, shaking his head. "Because I just got lost in your eyes."

"That sounds highly uncomfortable."

He couldn't suppress the grin that formed on his face as his boyfriend groaned. Of course Shinichi knew what Kaito was doing – he just didn't understand _why._ And if Kaito was actually going to try and use those horribly clichéd pickup lines on _him_ (his _boyfriend,_ at that – they were already going out!) then he would make it as agonizing as possible for him.

"_Shinichiiii_," Kaito whined. "That's not how it goes."

"Tell me another one; I'll try to get it right this time. No guarantees, however."

He wondered just how many of those pickup lines Kaito had even written down. From the looks of things, it seemed like he had at _least_ ten pages in that pile. _He couldn't have_, Shinichi thought incredulously. _Not even _Kaito's_ that_ _crazy._

"If you were a tear in my eye," Kaito, ignorant to Shinichi's internal monologue, sighed dramatically, crossing the short distance between them to rest his hands on his boyfriend's chest. "I would not cry in fear of losing you."

"… That one sucked," Shinichi frowned. "I didn't even get to respond to that one."

"Yeah, well, you screwed up the other ones already, so I didn't think you deserved to respond," Kaito stuck his tongue out playfully at the detective.

Shinichi smirked. "Alright, fine. Let's see who can come up with the better pickup lines. Alright?"

"Sure. You go now."

"Okay…" The detective of the east closed his eyes and racked his brain for the cheesiest and most awful line he could think of. He'd probably read a book about horrible pickup lines at some point in his youth (both of them), he just had to remember—"Alright. Are your legs tired?"

"Yes," Kaito nodded, sitting down in a chair and kicking his feet up and onto Shinichi's lap. Shinichi frowned and shoved them off.

"Because you've been running through my mind all night."

Kaito yawned. "Lame. Here, I've got a better one. Ahem," he paused for dramatic effect. "Are you a library book?"

"Don't use library pickup lines while we're inside a library."

"Because I'd like to check _you_ out."

Kaito winked, and Shinichi groaned. "Sorry, I'm on display only."

"I'm a thief; I don't care. I'm a thief, and I'm here to steal your heart."

Shinichi snorted. _You already have it. _He leaned over to where he had previously been doing his homework before Kaito started up with this game of his. The pencil fell neatly between his fingers, and he started writing down letters of the English alphabet onto the back of his calculus equations sheet. Kaito leaned over with a raised eyebrow, and the detective turned to him and explained what he was doing: "I'm trying to rearrange the alphabet so that U and I are together."

"Aw, that's sweet," Kaito sighed romantically and placed his hands over his heart. "But _wow_, is it getting hot in here? Or is it just me?"

Shinichi blinked. "You did that one wrong."

"No, I didn't."

"Yes, you did! You're supposed to ask if _I'm _the hot one."

"Wow, Shinichi, that's kind of vain, don't you think?"

Kaito burst out laughing, and Shinichi groaned again. He'd walked straight into that one – though with how similar they looked, he could say the same exact thing for the magician himself. "Hey, I think I lost my phone number," he said instead, thumbing the phone sticking out of his pocket. "Can I have yours instead?"

"Oh, that reminds me – which number did you lose? I think you still have that Conan phone lying around here somewhere."

Shinichi choked. "It doesn't get much use anymore."

"I kind of miss Conan," Kaito smiled fondly. "He was so small and cute… when's he coming back, do you think?"

"Not for a very, _very_ long time." He'd gotten the antidote – along with an _anti _-antidote, in case he ever wanted to return back to being Conan for whatever reason. It had nearly been two years since the fall of the Black Org, and he _still_ couldn't find a use for it. "Are you accepting applications for your fanclub?"

"What kind of pickup line is that? That one doesn't even _have_ to be a pickup line, you can use that on just about anyone," Kaito frowned. "You suck at this, Shinichi."

"Like you're any better," Shinichi huffed.

"I _am_ better! Leave all the words and flowery language to me – I _live_ off that stuff. You can stay in your boring world of logic and calculations. I'll still drop by every once in a while to mess it all up though, of course." He eyed his stack of papers and beamed. "Ooh, this one would have been great for Conan! I lost my teddy bear; can I cuddle with you instead?"

"Who are you to be using pickup lines on a six year old boy?" Shinichi coughed. "Is there something I should know about you, Kaito?"

"Hey, if you were still Conan, I'm sure things would have turned out exactly the same way," Kaito jabbed his finger at Shinichi's chest. "Just… I'd have to be more careful not to crush you, that's all."

"In…?"

"Everything." Kaito smiled and refused to elaborate. "Moving on! You're hot, I'm hot; let's make beautiful babies." Shinichi actually snorted loudly at that one, and Kaito burst out laughing at his response. "You liked that one! You totally liked that one."

"No, I didn't," Shinichi shook his head, trying to regain his bearings. "Good _god_, Kaito—"

"Let biology have no part in this, okay? We can have whatever we want, if we just believe~ So kiss me if I'm wrong, but dinosaurs still exist, right?"

Shinichi finally calmed himself down and rolled his eyes, his shoulders still shaking with slight laughter. "If you want them to, then sure. You just have to _believe_, remember?"

"No, you're supposed to kiss me and prove me wrong with that logic of yours," Kaito frowned. "You're doing it wrong again. So fix it."

"I don't have to prove you wrong just to have a reason to kiss you," Shinichi mumbled, but he leaned in to meet his boyfriend's lips anyway. Kaito smiled and hummed into the kiss, reaching up to wrap his arms around Shinichi's neck. Shinichi did likewise, pulling him closer, before—

"_Ahem._"

The two boys stopped and turned to see the source of the noise. They were greeted with the rather awkward expressions of the friends they had dragged along to the library to form their little study group with. Hakuba, of course, was the interrupter.

"Damn it, Hakuba," Kaito scowled. "You always ruin everything."

"Excuse you," Hakuba narrowed his eyes, but the intensity of his expression was betrayed by how _red_ his cheeks had turned. "But some of us were under the impression that we actually were invited here to _study_, not to watch you two make out."

Shinichi, for his part, actually looked embarrassed. He couldn't believe he had forgotten that they had guests – guests _he himself_ had invited, at that! "Sorry about that, I—"

"Thirteen," Hattori was muttering. "_Thirteen_ pickup lines is what it took for you two to finally make out. You guys gotta do better than that; start over again."

"H-Heiji-kun!" Ran gaped at the Osakan detective incredulously. "Not in the library, _please_…" She put up a good front of not having any interest in the two's relationship at all whatsoever, but Shinichi knew better.

He'd gotten one of her misaimed texts meant for Kazuha detailing everything she'd like to see them do once, after all.

It was quite the eye-opener about his childhood friend, but he supposed that after the whole Conan fiasco, there were no secrets between anyone anymore.

He almost missed all the secrecy. But only sometimes.

"I agree with Ran-san," Hakuba coughed awkwardly. "If you two must, please… go into a bathroom or something."

"That's horribly unhygienic," Kaito made a face. "Why don't you three go study in there, and Shinichi and I will stay out here?"

"Or we can just go back to studying…" Shinichi sighed, but he knew it was a hopeless battle.

Kaito stood up on his chair indignantly. "We don't have to take this! This is _your_ library, Shinichi! You can do whatever you want in it!"

"Not in front of your _guests_!" Hakuba shouted back, standing up on his own chair. His notes fell in a cluttered mess all over Hattori, and the Osakan sputtered. "You have to learn proper hosting etiquette, and _making out with your boyfriend while they watch_ is _not_ one of them!"

Shinichi simply shook his head, deciding not to comment. It was obvious that they would not be getting any more studying done that day. He gave up. "Want to head out to Poirot's or something?" He asked the other two, the only ones left with him who were not currently in a shouting match with each other. "I heard they're having a sale on sandwiches today."

"Ooh, I like the sound of that."

Hakuba was still yelling even as they left. "You printed out ten _pages_ worth of pickup lines, and you had to start going through them in our presence?"

"Joke's on you, Hakuba!" Kaito flung the papers at him, and they all scattered to reveal that every single one of them was bare. "I didn't print a single thing!"

* * *

_A/N: A silly little oneshot to tide people over for the next chapter of Childish War, I hope. C: (And Chronophobia, if you're following that as well. But Chronophobia isn't on this site.)_

_I'll most likely do more of these… I missed writing oneshots. So expect to see many more Kaishin blurbs from me! (And KIDCon, and… other pairings I like, haha.)_

_I hope you enjoyed!_


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